Year	% of land area
1961	42.349726775956285
1962	42.41530054644809
1963	42.48087431693989
1964	42.54644808743169
1965	42.6120218579235
1966	42.6775956284153
1967	42.743169398907106
1968	42.76502732240437
1969	42.87431693989071
1970	42.939890710382514
1971	43.005464480874316
1972	43.071038251366126
1973	43.12568306010929
1974	43.18032786885246
1975	43.23497267759563
1976	43.2896174863388
1977	43.34426229508196
1978	43.39890710382514
1979	43.45355191256831
1980	43.486338797814206
1981	43.51912568306011
1982	43.55191256830601
1983	43.58469945355191
1984	43.61748633879781
1985	43.650273224043715
1986	43.68306010928962
1987	43.72677595628415
1988	43.77049180327869
1989	43.77049180327869
1990	43.31147540983606
1991	42.841530054644814
1992	42.38251366120219
1993	43.267759562841526
1994	43.19125683060109
1995	42.885245901639344
1996	40.76502732240437
1997	39.147540983606554
1998	40.68306010928961
1999	42.21857923497267
2000	43.23912568306011
2001	42.11825136612022
2002	42.37945355191257
2003	41.67956284153006
2004	42.29081967213115
2005	41.80485405050836
2006	41.080791516344156
2007	40.02317699792282
2008	40.733136547501914
2009	40.34916475597773
2010	39.89704116169888
2011	39.84452451140954
2012	40.008843760235834
2013	40.40272822940182
2014	39.99624477106203
2015	39.72224405494861
2016	39.506645881911155
2017	40.1000899508327
2018	40.79190027683897
2019	43.12531657453256
2020	43.16609028269014
2021	43.253856751115656